Problem to pass values by URL (GET) in PHP

I try to do the following:

From a query, I create a table, to which at an option, I am adding a link to print a pdf,

$indices .= '<tr>
                    <td>' .$row[id_presupuesto]. '</td>
                    <td>' .$row[fecha]. '</td>
                    <td>' .$row[referencia]. '</td>
                    <td>' .$row[ncomercial]. '</td>
                    <td>' .$row[precio_final]. ' €</td>
                    <td>' .$row[estado]. '</td>
                    <td><a href="pdf/documentos/presupuesto.php?id=$idd"><i class="fas fa-eye imprimir"></i></a></td>
                    <td><i id="'.$row[id_presupuesto].'" class="fas fa-trash-alt"></i></td>
                </tr>';

Specifically, it is this line:

<td><a href="pdf/documentos/presupuesto.php?id=idd"><i class="fas fa-eye imprimir"></i></a></td>

I have added the entire variable $indices to make it clear, that the code is HTML within PHP, especially for the subject of the quotes.

Right now, in the URL, I pass ?id=$idd How can I get the correct% "id" out?

• Add that $idd comes from:

$idd = $row[id_presupuesto];

Greetings.